Abstract
Alkali metal cation extraction behaviour for two series of 1,3-alternate, mono-ionisable calix[4]arene-benzocrown-6 compounds is examined. In Series 1, the proton-ionisable group (PIG) is a substituent on the benzo group of the polyether ring that directs it away from the crown ether cavity. In Series 2, the PIG is attached to one para position in the calixarene framework, thereby positioning it over the crown ether ring. Competitive solvent extraction of alkali metal cations from aqueous solutions into chloroform shows high Cs+ efficiency and selectivity. Single-species extraction pH profiles of Cs+ for Series 1 and 2 ligands with the same PIG are very similar. Thus, association of Cs+ with the calixcrown ring is more important than the position of the PIG relative to the crown ether cavity. Solid-state structures of two unionised ligands from Series 2 are presented. Also described is a crystal containing two different ionised ligand-Cs+ complexes.
Original language | English |
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Pages (from-to) | 59-64 |
Number of pages | 6 |
Journal | Supramolecular Chemistry |
Volume | 27 |
DOIs | |
State | Published - Feb 1 2015 |
Funding
This research was supported at TTU by the Office of Biological and Environmental Research of the US Department of Energy [grant number FG02-03ER63676]. The research contribution of RC at ORNL was supported by the Environmental Management Science Program of the Offices of Science and Environmental Management of the US Department of Energy (contract number DE-AC5-00R22725).
Keywords
- alkali metal cation extraction
- caesium-selective extractant
- calixcrown ligand
- crown ether